If you use content checks, we recommend that you use a dedicated IMAP account that is only checked by PRTG. Editing existing mails in the mailbox of the monitored IMAP account can lead to false alarms or malfunctions of this sensor type.

This sensor type might not work properly when monitoring subfolders of mailboxes. If it has to check subsequent emails with identical subjects, later on incoming emails might not be recognized.

Emails that arrive during the Daylight Saving Time (winter time to summer time) change may not be processed properly. If you experience this issue, please delete the respective emails.

This sensor type does not support Secure Remote Password (SRP) ciphers.

The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.

Sensor Settings

On the details page of a sensor, click the Settings tab to change its settings.

Usually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. See below for details on available settings.

Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value.

There are default tags that are automatically predefined in a sensor's settings when you add a sensor. See section Default Tags below.

You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.

It is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with round parentheses (()) or angle brackets (<>).

Priority

Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).

Default Tags

imapsensor, mailsensor

Connectivity

Timeout (Sec.)

Enter a timeout in seconds for the request. If the reply takes longer than this value defines, the sensor will cancel the request and show a corresponding error message. Please enter an integer value. The maximum value is 900 seconds (15 minutes).

Port

Enter the number of the port that the sensor uses to connect via IMAP. For non-secure connections, usually port 143 is used. For SSL connections it is usually port 993. The actual setting depends on the server you are connecting to. Please enter an integer value. We recommend that you use the default value.

If you do not get a connection, please try another port number.

Security

Define the security level for the sensor connection. Choose from:

Use Transport-Level Security if available using StartTLS (default): Choose this option to try to connect to the server using TLS and StartTLS. If the server does not support this, the sensor will try to connect without encryption.

Use Transport-Level Security if available: Choose this option to try to connect to the server using TLS. If the server does not support this, the sensor will try to connect without encryption.

Enforce Transport-Level Security using StartTLS: Choose this option to try connecting to the server using TLS and StartTLS. If the server does not support this, the sensor will show a Downstatus.

Enforce Transport-Level Security: Choose this option to try to connect to the server using TLS. If the server does not support this, the sensor will show a Downstatus.

If the sensor connects to a server via StartTLS, the connection is established unencrypted first. After the connection is established, the sensor sends a certain command (StartTLS) over the unencrypted connection to negotiate a secure connection via the SSL/TLS protocol.

If the sensor uses TLS without StartTLS, the negotiation of a secure connection happens immediately (implicitly) so that no commands are sent in unencrypted plain text. If there is no secure connection possible, no communication will take place.

Sensor Behavior

General Behavior

This sensor can additionally check the content of all incoming emails. Choose from:

Check connectivity only, do not process emails (default): Only check availability of the IMAP server and check if a login is successful. Do not process any emails in the IMAP email account.

Count emails in this mailbox: Count the emails in the defined mailbox.

Process emails in this mailbox: Log in to the IMAP email account and check the emails that it contains. Define further options below.

Sensor Result

Define what PRTG will do with the sensor results. Choose between:

Discard sensor result: Do not store the sensor result.

Write sensor result to disk (Filename: Result of Sensor [ID].txt): Store the last result received from the sensor to the Logs (Sensors) directory in the PRTG data folder on the probe system the sensor is running on (on the Master node if in a cluster). File names: Result of Sensor [ID].txt and Result of Sensor [ID].Data.txt. This is for debugging purposes. PRTG overwrites these files with each scanning interval. For more information on how to find the folder used for storage, see section Data Storage.

This option is not available when the sensor runs on the Hosted Probe of a PRTG hosted by Paessler instance.

Authentication

Username

Enter a username for IMAP authentication. Please enter a string.

Password

Enter a password for IMAP authentication. Please enter a string.

Folder Name

Enter the name of a folder in the mailbox (for example, the IMAP folder) that the sensor will check. Default value is Inbox. Unless you set a last message date check below, the sensor will always look at all emails contained in the mailbox.

Ensure that you do not manually edit emails in this mailbox with another email client because this can result in malfunctions of this sensor's email identification.

Filter Emails in Inbox

This settings section is only visible if you choose to process the emails in the mailbox.

Only Include Emails with Matching "From"

Define if you want to check the "From" field of the emails. When using a search, the sensor will scan all emails from the newest to the oldest. Choose from:

Do not check (default): Do not process this field in emails.

Check using string search: Process this field in emails using simple string search.

Check using regular expression: Process this field in emails using a regular expression.

PRTG supports PCRE regex. You cannot use regex options or flags. For more details, see section Regular Expressions.

The sensor finishes the scan with the first match! This means that after it has found a match in one email, the sensor will not perform any further checks in older emails.

Search for

This field is only visible if you enable a "from" check above. Enter a search string using the method defined above.

Only Include Emails with Matching "Subject"

Define if you want to check the "Subject" field of the emails. When using a search, the sensor will scan all emails from the newest to the oldest. Choose from:

Do not check (default): Do not process the subject of emails.

Check using string search: Process the subject of emails using simple string search.

Check using regular expression: Process the subject of emails using a regular expression. For more information about syntax, see section Regular Expressions.

PRTG supports PCRE regex. You cannot use regex options or flags. For more details, see section Regular Expressions.

The sensor finishes the scan with the first match! This means that after it has found a match in one email, the sensor will not perform any further checks in older emails.

Search for

This field is only visible if you enable a "subject" check above. Enter a search string using the method defined above.

Only Include Emails with Matching Email Body

Define if you want to check the email body of the emails. When using a search, the sensor will scan all emails from the newest to the oldest. Choose from:

Check using regular expression: Process the email body using a regular expression. For more information about syntax, see section Regular Expressions.

PRTG supports PCRE regex. You cannot use regex options or flags. For more details, see section Regular Expressions.

The sensor finishes the scan with the first match! This means that after it has found a match in one email, the sensor will not perform any further checks in older emails.

Search for

This field is only visible if you enable checking the email body above. Enter a search string using the method defined above.

Only Include Recent Emails

Define if you want to check all emails in the mailbox, or only mails that were received within the last few hours. Choose between:

Do not check message age (default): Always check all emails that the mailbox contains.

Emails must be younger than: Only check emails that were received in the last few hours. Define below.

Maximum Age in Hours

This field is only visible if you enable the message age check above. Enter the maximum age in hours. The sensor will only process emails that are younger. Please enter an integer value.

If No Email Matches the Above Filters

Define which status the sensor will show if it does not find any email in the mailbox that matches the defined filters. Choose from:

Set sensor to up status (default)

Set sensor to warning status

Set sensor to down status

Message

This field is only visible if you define a Warning or Down status as no matching behavior above. Define the message that the sensor will show if it did not find any matching emails together with a Warning or Down status as you define above.

Validate Latest Email

This settings section is only visible if you choose to process the emails in the mailbox.

The sensor will only validate the latest email that matches the filters above! If the sensor does not find a matching email, it will not perform any email validation.

For the Latest Email that Matches, Set Sensor to "Warning" Status

Define in which cases the sensor will show a Warningstatus. Choose from:

Never (default): Never set this sensor to a Warning status based on email content.

Always: Always set this sensor to a Warning status in case any emails could be identified.

If subject contains: Set the sensor to Warning if the subject of the found email contains the search text you define below.

If subject does not contain: Set the sensor to Warning if the subject of the found email does not contain the search text you define below.

If email body contains: Set the sensor to Warning if the body of the found email contains the search text you define below.

If email body does not contain: Set the sensor to Warning if the body of the found email does not contain the search text you define below.

Check Method

This setting is only visible if you select an if condition above. Define how you want to check for the above condition. Choose between:

Regular expression: Check the email subject or body using a regular expression. For more information about syntax, see section Regular Expressions.

PRTG supports PCRE regex. You cannot use regex options or flags. For more details, see section Regular Expressions.

Search Text

This setting is only visible if you select an if condition above. Enter a search string using the method defined above.

Warning Message

This setting is only visible if you select a warning condition above. Define the message that the sensor will show for a Warningstatus.

Based on Message Age, Set Sensor to "Warning" Status

Define if you want to check the age of the latest matching email in the mailbox. Choose between:

Never (default): Do not check the age of the email.

If email is older than: Set the sensor to Warningstatus if the found email is older than you define below.

Message Age in Hours

This field is only visible if you enable the message age check above. Enter the maximum age in hours. If the processed email is older, the sensor will show a Warningstatus. Please enter an integer value.

Ensure you do not manually edit emails in this mailbox with another email client because this can result in malfunctions of the message age check.

Regular expression: Check the email subject or body using a regular expression. For more information about syntax, see section Regular Expressions.

PRTG supports PCRE regex. You cannot use regex options or flags. For more details, see section Regular Expressions.

Search Text

This setting is only visible if you enable an if condition above. Enter a search string using the method defined above.

Error Message

This setting is only visible if you select a down condition above. Define the message that the sensor will show for a Downstatus.

Sensor Display

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel will always be displayed below the sensor's name. The available options depend on what channels are available for this sensor.

You can set another primary channel later by clicking the pin symbol of a channel in the sensor's Overview tab.

Graph Type

Define how different channels will be shown for this sensor.

Show channels independently (default): Show an own graph for each channel.

Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This will generate an easy-to-read graph that visualizes the different components of your total traffic. This option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channel Settings settings).

Stack Unit

This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings, see section Inheritance of Settings for more information. To change a setting only for this object, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You will then see the options described below.

Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations.

If a Sensor Query Fails

Define the number of scanning intervals that a sensor has time to reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Downstatus. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose from:

Set sensor to down immediately: The sensor will show an error immediately after the first failed request.

Set sensor to warning for 1 interval, then set to down (recommended): After the first failed request, the sensor will show a warning status. If the following request also fails, the sensor will show an error.

Set sensor to warning for 2 intervals, then set to down: Show an error status only after three consecutively failed requests.

Set sensor to warning for 3 intervals, then set to down: Show an error status only after four consecutively failed requests.

Set sensor to warning for 4 intervals, then set to down: Show an error status only after five consecutively failed requests.

Set sensor to warning for 5 intervals, then set to down: Show an error status only after six consecutively failed requests.

Sensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval until they show an error. It is not possible to set a WMI sensor to Down immediately, so the first option will not apply to these sensor types. All other options can apply.

If a sensor has defined error limits for channels, it will always show a Down status immediately, so no "wait" option will apply.

If a channel uses lookup values, it will always show a Down status immediately, so no "wait" options will apply.

Schedules, Dependencies, and Maintenance Window

Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted. The corresponding settings from the parent objects will always be active. However, you can define additional settings here. They will be active at the same time as the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.

Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active at the same time.

Maintenance Window

Specify if you want to set up a one-time maintenance window. During a maintenance window, the current sensor and all child objects will not be monitored. They will be in a Paused status instead. Choose between:

Not set (monitor continuously): No maintenance window will be set and monitoring will always be active.

Set up a one-time maintenance window: Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for a currently running maintenance window.

To terminate a current maintenance window before the defined end date, change the time entry in Maintenance Ends to a date in the past.

Maintenance Begins

This field is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance Ends

This field is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.

Dependency Type

Define a dependency type. You can use dependencies to pause monitoring for an object depending on the status of another object. You can choose from:

Use parent: Use the dependency type of the parent device.

Select a sensor: Use the dependency type of the parent device. Additionally, pause the current sensor if another specific sensor is in a Down status or in a Paused status caused by another dependency. Select below.

Master sensor for parent: Make this sensor the master object for its parent device. The sensor will influence the behavior of its parent device: If the sensor is in a Down status, the device will be paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor will be paused if the parent group is paused by another dependency.

Testing your dependencies is easy! Simply select Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later, all dependent objects should be paused. You can check all dependencies in your PRTG installation by selecting Devices | Dependencies from the main menu bar.

Dependency

This field is only visible if you enable Select a sensor above. Click the Search button and use the object selector to select a sensor on which the current sensor will depend.

Dependency Delay (Sec.)

This field is only visible if you enable Select a sensor above. Define a time span in seconds for dependency delay.

After the master sensor for this dependency comes back to an Up status, monitoring of the dependent objects will be additionally delayed by the defined time span. This can help avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value.

This setting is not available if you set this sensor to Use parent or to be the Master sensor for parent. In this case, please define delays in the parent Device Settings or in its parent Group Settings.

Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown. It contains all user groups from your setup. For each user group, you can choose from the following access rights:

Inherited: Use the access rights settings of the parent object.

None: Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.

Read: Users in this group can see the object and review its monitoring results.

Write: Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.

Full: Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.

You can create new user groups in the System Administration—User Groupssettings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.

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